I'm not sure this is nugget of information that is lost, just something I overlooked, perhaps, when reading about ADC. Most online references, only make mention of the carry bit being set, not that it was used in the actual computation.
Direct from the MCS6500 MOS programming manual:
"This instruction adds the value of memory and carry from the previous operation [emphasis mine] to the value of the accumulator and stores that result in the accumulator.
The symbolic representation for this instruction is: A + M + C -> A"
All I can say is that its really good to have copies of these very old books.
Odd that many books wouldn't mention it. Most that I read clearly stated that before using the add instruction, you have to clear the carry, and before subtract you have to set it for accurate results.
Cool that it was figured out though. That's why I love these forums, there's a wealth of information and also, many people willing to share that information. Let's keep those 6502s humming
Damn. Wouldn't you know it. Got busy on other stuff, let this run to 1.4 Billion iterations. It got down to a normal of 0.2, so this "can" be a perfect conversion. I let it run too long, so there is a single bad line in it. Also, forgot to center the image, so I will be restarting it. Restarting now. Here's screenshots of Rasta and Altirra. Notice, the bad yellow line is NOT in the Rasta middle window
It'd be more excusable it Xformer didn't have literally decades of poor emulation and broken promises behind it, the worst being for the customers who paid for it...
This must be the reason for the difference in styles (posting styles, i.e., perceived attitudes, etc.) Been around a long time, but was never a paying customer of Xformer, so missed all the drama from back then.
One of the "millions" here. I love all my new upgrades, but I also have an unmodified 16kB 400 with membrane keyboard. I was lucky - had my 1st machine since 82, and expanded my collection in the mid 90s when this "crap" was being thrown away. No need to worry about stock or modified when you have over a dozen machines to choose from